Separation of vat dyestuff isomers of the naphthoylene diarylimidazole series and the product obtainable thereby



' stuffs.

Patented Sept. 26, 1933 UNI-ITEDT STATES,

P T ENT 1 SEPARATION OF VAT DYESTUFF ISOM'ERS OF; THE NAPHTHOYLENE-DIARYLIM- IDAZOLE SERIES AND THE. E OBTAINABLE THEREBY Wilhelm Eckertand Heinrich Sieber;

raonno'r I Frankfort-V on-the-Main-Hochst, Germany, assignols to GeneralAniline Works, -Inc., New York,- Y., I, 4

a corporation of Delaware Drawing. Application October 5, 1931, SerialNo. 567,128, and

in Germany October s Claims. (01. 260 44) I is obtained. When condensinga substituted r ortho-phenylenediamine compound with 1.4.5.8-

naphthalene-tetra-carboxylic f acidin many cases the same holds true, i.e. there is likewise obtained a-mixture ofthe isomers. I 7 r The presentinvention relates to a process of separating the dyestuif mixturesobtainable lac} cordingto U. S. Patent No. 1,588,451 into theircomponents. Another object of our invention are new products obtainableaccording to our new process. r

We have found that the dyestuff mixtures obtainable according to U. S.Patent No/11,588,451

can be separated into their components by a'suitable treatment with analkali metal hydroxide.

The nature of our new process has not been definitely cleared up.Mostprobably by the Morementioned treatmentwith analkali metal hydroxidethedyestufi isomers which probably-possess the following configuration:v

wherein R represents an aromatic hydrocarbon radical which may containvsubstituents are'converted into newalkali metal addition compounds ofthe dyestufi isomers propen. We assume that these new compounds possessthe following cone flgurationz' wherein X represents the followingbivalent radi w th " u -'1" o' o,.1 "MO 1 N N- R I R represents anaromatic hydrocarbon radical, i especially a phenylene or a polynuclearhydrocarbon radical, which may contain substituents, and M stands for analkali metal.

The new compounds represent always colorless products, whereas thedyestufi isomers are intensely colored products, j The new products aresoluble in water of a definite alkalinity. The 6 clear. solutions slowlyundergo a hydrolyzation process. The hydrolyzation is accelerated bydiluting or acidifying the before-.mentioned solutions. The newcompounds may be used for dyeing purposes as well as'for cloth printingThe alkali metal addition products of the dyestufi isomers difiersubstantially as to their corresponding solubility; the difierence inevery instance, as far as it is known to'us, being so pronounced thatthis property of the new products can be utilized 6 for separating ina-very simple way-the mixture formula:

the dyestuffs proper by a-suitable hydrolyzation process. p

In the process of preparing the new alkali metal addition products onemay work at'room temperature as well as at elevateditemperature. Ingeneral, the formation of the. addition products is accelerated by theuse of an elevated temperature temperature of alcohol.

advantage to use either water as the diluent, as hereinafter shown inExample 4, or to use a sol-. vent which is mixable with water such asethyl alcohol as it is shown, for instance, in the following Examples 1to 3.

The following examples serve to illustrate the invention, but they arenot intended to limit it thereto the p'arts'being by weight:

(1) 10 parts of the mixture ofthe isomeric dyestufis obtainable bycondensing 1.4.5.8-naphthalene-tetracarboxylic acid with 'ortho-phenyLenediamine according to U. S.- Patent No. 1,588,451, are warmed in afinely divided form with parts of caustic potash and about 50 parts ofethyl alcohol until the red color of the solution has disappeared,Thereuponyabout 90 parts of ethyl alcohol are added and the ,whole isheated for ;hour to..70'C.-80 C. After cooling, the

solution is filtered with suction and the remaining solid matter iswashed with a small quantity of ethyl alcohol containing causticpotashi. From the filtrate the red dyestuif is precipitated by 40 meansof water, whereas the orange dyestuff remains on the filter'in the formof its KOH compound. It is likewise'hydrolyzed by means of water.Instead of ethyl alcohol other alcohols may be used, for instance,methyl alcohol; instead of caustic potash there may be used otheralkalies,

such as caustic soda.

The dyestuffs thus obtained have the same properties as those obtainedaccording to U. S. Patent No. application Serial No. #141,712 filed onApril 4,1930, in the name of Wilhelm Eckert, Heinrich Greune and WillyEicholz for Newj'vat dyestuffs and a process of preparingthem.

The addition product of the orange part of the dyestuff mixture probablyhas the following forming colorless; quadratic tablets which do not melteven at 350 'C. The product may be .used for dyeing purposes as well asfor clothprinting.

alkali metal addition products are converted into 7 such as, forinstance, 60 C. to '70 C. or the boiling In the process-of pre-. paringthe new addition products it may be of probably the followingconstitution:

forming feeble yellow prisms which, when introduced into water, remaindissolved for a pro longed time and afterwards hydrolyze gradually tothe Bordeaux-red dyestuff proper.

(2) 25 parts or the mixture of isomeric dye stuiTs obtainable bycondensing 1.4.5.8naphtha lene-tetracarboxylic acid with1.2-dichloro-4.5- diaminobenzene according toU. S. Patent No. 1 51,588,451, are' warmed with. 5.0,, parts of caustic soda and, about 310parts of ethyl alcohol until the formation of the colorless additioncompound is terminated. It is filtered with suction and the remainingsolid matter is decomposed bymeans i of water into an orange coloreddyestuff. From the filtrate there is precipitated on addition of water,the dark red isomeride.

(3) The mixture of the isomeric dyestuffs obtainable bycondensing 1.4.5.8-naphthalene-tetracarboxylic acid with4-etho'xy-1.2-diaminobenzene according to U. S. Patent'No.1,588,451 maybe decomposed in a manner similar. to that described in Example 1, byway of analkali-addition compound, into a yellowish brown dyestuff and abluish brown dyestuff. e I (4) 50 parts of the mixture of 'thedyestuffsobtainable by condensing 1.4.5.8 naphthalene-tetracarboxylic acid withortho phenylenediamine (according to U.1S. Patent No. 1,588,451) areintroduced in a finely divided state into a solution of 200 parts ofcaustic potash in 200 parts'of ,water, The addition of about 20 parts ofethyl alcohol promotes the wetting of the dyestuff parwith. the alkali.The whole is heated for 2 to' 3 hours at 120 C; thereupon, 140 parts ofwater are added and the whole is cooled to20 C. After standing foraprolonged time, the 'KOI-I'compound of the one of'the isomerscrystallizes and separates. It is filtered by suction, washed withalcohol containing alkali and worked up as described in Example 1. Y t 1In the same or avery similar manner the following dyestuffs may beseparated into their isomers:

1.4.5.8 naphthoylene dimethyl dib'enzimidazole. 1 1 1.4.5.8naphthoylene-tetramethyl dibenzimidazole.

' 1.4.5.8-naphthoy1ene-dichloro-dibenzimidazole.1.45.8-naphthoylene-dibromo-dibenzimidazole.l4.5.8-naphthoylene-dinitrmdibenzimidazole.

1.4.58-naphthoylene dim'ethoXy-dibenzimidazole.

ill) imidazole.

1 .4.5.8-naphthoylene-dinaphthimidazole.

We claim:

1.4.5.8 napthoylene-dibromoedichloro-dibenz5 1. As new products, thecompounds of the following probable formula R represents abivalentradical of the benzene and naphthalene series, bound in ortho-positionsto the nitrogen atoms of the molecule, and M stands for an alkali metal,being nearly colorless products dissolving in water of a definitealkalinity to clear solutions which slowly undergo a I hydrolyzationprocess which process is accelerated purposes as well as for clothprinting.

2. As a new product, the compound of the fol- L lowing probable formula:

N N I I hydrolyzing quickly with conversion into the orange dyestuffproper.

3. As a new product, the compound of the following probable formula:

said product being capableof being used for dyeing purposes as well asfor cloth printingflorming feebly yellow prisms which, when introducedinto water, remain dissolved fora prolonged time and afterwardshydrolyze gradually tothe. Bor v deaux-red dyestufi'proper.

4. The process which comprises causing an al- 1 1 kali metal hydroxideto react with a mixture of isomeric dyestuffs of the following generalforv mulae: p a

' i n R N OC s o 0 I and I t ".96 .oow'o' -Y as A g X a R R g I whereinR represents a bivalent radical of the 109 benzene and naphthaleneseries, bound in ortho f positions to the nitrogen atoms of themolecules.

5. The process which comprises causing caustic potash to react with amixture of isomeric 106 dyestuffs of the following general formulae:

wherein R represents a bivalent radical of the benzene and naphthaleneseries, bound in ortho positions to the nitrogen atoms of the molecules.

6. The process which comprises causing caustic potash to react with amixture of isomeric dyestuffs of the following general formulae:

wherein R represents a bivalent radical of the benzene and naphthaleneseries, bound in ortho positions to the nitrogen atoms of the molecules,

in the presence of a diluent of the group conof isomeric dyestufis ofthe ;following' general formulae:. 7 .7

and

wherein R represents a bivalent radical of the benzene and naphthaleneseries, bound in ortho positions to the nitrogen atoms'of the molecules,and separating the products thus obtained. by meansof their differentsolubility.

8.- The process which comprises causing an alkali metal hydroxide toreact with a mixture wherein R represents a bivalent radical of thebenzene and naphthaleneseries, bound in ortho position to the nitrogenatoms of the molecules,

and separating the products thus obtained by means of their diiferentsolubility and subjecting I the separated products to a hydrolyzationprocess.

WILHELM ECKERT. HEINRICH SIEBER.

